Automatic sewing machine system



P 3, 1968 c. J.BRYAN ETAL AUTOMATIC SEWING MACHINE SYSTEM 2 Sheets-Sheet1 Filed Jan. 25, 1966 INVENTORS. CARNEY J. BRYAN BY HERMAN ROVINATTORNEYS. V

Se t. 3, 1968 c. J. BRYAN ETAL 3,399,640

AUTOMATIC SEWING MACHINE SYSTEM Filed Jan. 25, 1966 2 Sheets-Sheet 2CARNEY J. BRYAN HERMAN ROVIN BY ATTORNEYS.

United States Patent 3,399,640 AUTOMATIC SEWING MACHINE SYSTEM Carney J.Bryan, 4607 Mercury Drive, Greensboro, N.C.

27400, and Herman Kevin, 51 Karen Drive, East Norwalk, Conn. 06851 FiledJan. 25, 1966, Ser. No. 522,915

15 Claims. (Cl. 112-2) This invention relates to a fully automaticsewing machine for stitching fabric work material along any desiredpredetermined path extending in more than one dimension and having asystem for stopping the needle in a raised position for releasing thecompleted workpiece and then for engaging the next workpiece andre-starting the stitching,

This invention is an improvement in the automatic highspeed stitchingmethods and apparatus disclosed and claimed in copending applicationSer. No. 436,763, filed on Mar. 3, 1965.

In an automatic sewing machine system embodying the present inventionthe various pieces of the fabric work material are propelled withrespect to the stitching station by a clamp member movable in more thanone coordinate direction for producing the desired multi-dimensionalstitching pattern in the material. When the stitching pattern has beencompleted the needle is automatically secured in an upper position toprovide clearance between the tip of the needle and the clamp member.The clamp member is moved to release the completed fabric workpiece andto move over for engaging the next fabric workpiece and quickly to bringit into the stitching station and commence stitching it. Advantageously,during the movement to engage the next workpiece and to bring it intothe stitching station, the clamp member is driven independently of themechanism which propels the clamp during the stitching operation.

In this illustrative system to assure that the needle is positivelysecured and remains in its raised position during the unloading andreloading of the stitching station, the drive mechanism for the sewingmachine is rapidly braked to a stop, and a positive lock then engagesthe drive mechanism. It will be appreciated that the momentum of themoving parts of the sewing machine and its drive causes some motion totake place after the fastacting brake has been applied, This systemprovides that the lock does not become engaged until the motion of theparts has become slowed down below that speed at which the engagement ofthe lock would cause breakage. Moreover, this system provides that theneedle is raised to its upper position and is locked there in the eventthe sewing machine initially comes to rest with the needle in a loweredposition.

In this illustrative system the fabric work material is supported upon asurface, such as a smooth table top, and the clamp member engages thework material and moves it over the supporting surface by a frictiongrip which exceeds the friction force between the lower surface of thematerial and the supporting surface. During the stitching operation theclamp member is driven by cams and levers having cam followers engagingthe cams. Double-acting drive means provide the resilient spring forcefor causing the levers to follow the motion of the cams during thisstitching operation so as to produce the desired pattern. During theunloading and reloading operation the double-acting drive means takescontrol to disengage the levers from the cams and provides the drive forthe movement of the clamp member for moving it to deliver the completedfabric workpiece and to engage the next fabric workpiece and quicklybring it into the stitching station and to reengage the levers with thecams to commence stitching the work.

It is an object of the present invention to provide an improvedautomatic sewing machine system which sews loading.

The present invention enables t-he stitching operation to start at theedge or at any interior point in an expanse of work material, and thestitching automatically p-rogresses at a high rate of speed alongstraight lines and around bends and abrupt changes in direction toproduce the desired path of stitches extending in more than onecoordinate direction and which unloads and reloads the work material ina manner suitable for automatically fabricating parts and components ofgarments and the like in an automatic production system.

As used herein, the term fabric work material is intended to meanfabric, cloth, felt, canvas, leather, sheet or similar fabric-like goodsupon which the stitching work is performed. This term is intended toinclude all such types of goods able to accommodate small amounts ofdistortion in the plane of the goods themselves, regardless of whetherthe material of the goods is in one piece or multiple pieces, one layeror multiple layers, regardless of whether the goods are woven,non-woven, felted, in sheet form, porous, perforate or imperforate,natural or synthetic or blended,

The term stitching along a path extending in more than one dimension (inmultiple coordinates) is intended to mean that the path of the stitchesin the work material can be defined with respect to the general plane ofthe work material in terms of multiple coordinates, and regardless ofwhether the work material itself as a whole is planar or non-planarform. In other words the stitching path may include straight-linesegments, curved segments, angles, abrupt changes in directions,spirals, cusps, and the like.

In this specification and in the accompanying drawings, is described andshown an automatic sewing machine system embodying the presentinvention, but it is to be understood that this disclosure is notintended to be exhaustive nor limiting of the invention, but on thecontrary is given for purposes of illustration in order that othersskilled in the art may fully understand the invention and the manner ofapplying the system in practical use and will understand how to modifyand adapt it in various forms, each as may be best suited to theconditions of a particular manufacturing application.

The various objects, aspects, and advantages of this invention will bemore fully understood from a consideration of the followingspecification in conjunction with the accompanying drawings, in which:

FIGURE 1 is a perspective view of an automatic highspeed multiplecoordinate sewing machine system embodying the present invention.

FIGURE 2 is an elevational view, partially broken away, of a lockingmechanism, shown full size, which serves to lock the sewing machinedrive with the needle in its fully raised position; and

FIGURES 3 and 3A are schematic electrical circuit diagrams of thecontrol system.

In FIGURE 1, is shown an automatic sewing machine system 10, and thework material W which is being stitched is a plurality of layers offabric to be used in part of a garment. This work W is held by a rapidlymovable clamp member 12 which frictionally engages the top surface ofthe work and serves to slide the work in two coordinate directions overa work table 14. Thus, the work is moved past a reciprocating needle 16secured in the needle bar-of ahigh-speed sewing machine 18, and

this system is capable of producing a line of stitches S along anydesired stitching path P extending in two coordinate directions.

The clamp member 12 includes a lightweight rigid frame with a resilientcoupling medium 22 attached to the frame and pressing down onto the workW closely adjacent to the line of stitches S. The resilient couplingmedium 22 -is compliant in compression so as to accommodate differentthicknesses in the work material, for example where different numbers oflayers are present at difierent regions of the work. This couplingmedium 22 is also compliant in shear to accommodate the arresting ofsmall localized areas of the work W during each instant that the needle16 is inserted in the work while the remainder of the work is incontinuous movement at high speed. In this example the coupling medium22 is sponge rubber.

The automatic sewing machine system is capable of stitching the workmaterial W at a high rate of speed. The clamp member 12 is connected toa long, rigid light-weight arm 24 which is driven by drive'mechanismgenerally indicated at 25, as will be described in detail further below.

When the stitching pattern S has been completed, the needle 16 is raisedup out of the way and the thread is automatically cut, for example, asexplained in said copending application Ser. No. 436,763. The clampmember 12 is elevated so as to disengage the resilient coupling medium22 from the work to release the completed work. While the clamp member12 is elevated, it is brought into relative position above a new pieceof work material at a work receiving point. The clamp member is loweredonto this new work and is quickly brought back into operativerelationship with respect to the needle 16. It is noted that thecompleted work may be released at a different point on the work table 14from that at which the new work is engaged, or the delivery andreceiving locations may be the same, as may be desired in a particularproduction application.

During the stitching operation the work material W is being slid overthe table 14 past the needle 16 which is reciprocated up and down by theneedle bar. The needle point passes down through a throat opening in thetable 14. In this example lockstitches are formed between a top thread26 carried by an eye in the needle and a lower thread 27 supplied from abobbin mechanism below the table in conventional manner. The localizedregion of the work material which is brefiy penetrated by the needle 16is arrested in its movement by an annular arrester foot 28 surroundingthe needle. This arrcster moves up and down into contact with workmaterial W in timed relationship with the needle stroke as explained insaid copending application. In certain production installations thearrester foot 28 may be omitted, and the needle 16 itself serves toarrest the forward movement of that region of the work material beingpenetrated by the needle.

The work material W as a whole is driven by the differential in frictionbetween the coupling medium 22 and the top surface of the work W on onehand and that between the lower surface of the work and the table 14.The drive mechanism includes a pair of lightweight triangular camfollower levers 34 and 35 driven by a pair of cams 36 and 37 mounted ona common vertical shaft 40. The levers 34 and 35 are disposed ongenerally opposite sides of the cams 36 and 37 and are arranged andconnected so that the lever 34 produces mainly movement of the arm 24 ina direction parallel to its own length while the other lever 35 mainlyproduces angular move ment of the arm 24 about a pivot 41. The lever 34has the fixed pivot 42 and a follower roller 43, so that it producesvelocity multiplication at the pivot connection 41 with the arm.Consequently, the arm 24 is moved in a direction along its length at ahigher rate Of speed and with a longer relative movementthan thatimparted by the cam 36 to the roller 43.

The other lever has a cam follower roller 44, a pivot connection 45 to across link 46, and an intermediate fixed pivot 47. Thus; it hasapproximately equal lever arms to provide a velocity and movement at thepivot connection 45 which is approximately equal to that imparted by thecam 37 to the roller 44. This velocity is transferredby the cross link.46 to a pivot connection 48-on the arm 24. With this arrangement thereis a movement of the end of the arm 24 perpendicular to its length whichis at a higher rate of speed and with a longer relative movement thanthat imparted by the cam 37 to the roller 44. Advantageously, thisarrangement produces velocity and movement multiplication with respectto both coordinates of motion that are substantially equal.Consequently, the cams 36 and 37 may be of substantially the sameover-all size for a wide variety of stitching patterns, thus minimizingthe over-all sizes and masses of the levers, link 46 and arm 24 whileenabling large pattern areas to be sewn at high speed.

The arm 24 is a truss formed of tubular members and is tapered downtoward both ends and has a maximum width near the pivot connection 48 toresist bending stress where the lateral thnists are imparted. Thetriangular levers 34 and 35 are hollow, and the cross link 46 is tubularto provide maximum rigidity to mass ratio.

In order to hold the follower rollers 43 and 44 against their respectivecams and also to move them quickly away from their cams during unloadingand re-loading of the stitching station, double-acting drive means 49and 50 are pivoted. These drive means 49 and 50 produce spring-likeforces of approximately constant magnitude exerting a force on thefollower rollers 43 and 44 directed inwardly generally toward the shaft40. In this illustrative system these double-acting drive means arelengthy double-acting pneumatic cylinders and pistons, and the gaspressure on the piston provides the resilient springlike force. It ispossible to use other double-acting drive means, for example, such aslong solenoid coils and armatures which produce an approximatelyconstant pull over a range of movement to produce the force for holdingthe cam follower rollers 43 and 44 against their cams. However, thepneumatic cylinders and pistons of the desired length are availablecommercially and operate to advantage as shown.

-A piston rod 51 extends from the cylinder and piston 49 and isconnected to the lever 34 by a clevis 52 to push the roller 43 againstits cam. A similar piston rod 53 extends from the cylinder and piston 50and is connected by a clevis 54 to pull on the outer end of the lever 35so as to hold the roller 44 against its cam. The relationship as shownin FIGURE 1 is the operating position during the high-speed formation ofthe stitches S.

To prevent the cam movement from being influenced by the forces of thefollower rollers 43 and 44 bearing against them and thus reactingagainst back lash in the drive gearing, suitable steady friction brakingmeans are provided. For example, there is a disk caliper brake 56providing a constant drag force upon a disc 57 on the shaft 40 so thatany back lash present is always taken up in the same direction withrespect to the rotation of the shaft 40.

To provide downward force on the clamp member 12 mm a minimumv of masseffect on the arm 24 there is a strip spring 58 of the type which isself-winding on a drum to generate a generally constant tension forceregardlessof extension, available commercially. This tension spring 58is secured to a long, substantially vertical cable 59 which is connectedto the underside of the arm 24 so as to pull downwardly on this arm withrelatively constant force regardless of the horizontal position of thearm.

The driving power for the system 10 is provided by a main motor 60having a suitable belt drive connection 61 to a. remote-controlledclutch and brake unit 62, including a magnetically actuated clutch 63and a magnetically actuated brake 64, which are connected by a shaft 65to a speed-reducing gear mechanism 66. A slower speed output shaft 67 isconnected by a gear 68 and a change gear train 69 and 70 to a drivengear 71 on the shaft 40. i

From this gear box 66 also extends a higher speed main shaft 72, and sothe rotation of this main shaft 72 bears a known speed relationship withrespect to the rotation of the cam shaft 40. The main shaft 72 isconnected bya pulley 73, a timing belt 74, and a driven pulley 75 to theshaft 76 of a needle locking mechanism 77, which is shown in detail inFIGURE 2.

In order to drive the sewing machine 18 at'a known relationship withrespect to the cam shaft 40, a drive path is provided from the shaft 76through a pulley 78 and a timing belt 79 to a driven sheave 80 on thecrank shaft 81 of the sewing machine. For providing a control functionas discussed below when the speed of the shaft 76 is below apredetermined level, there is a speed-sensing switch 83 which is drivenby a belt 84 from the shaft 76.

The earns 36 and 37 are individually removably secured to the shaft 40at a fixed angular orientation. To change the sewing pattern forstitching different pieces of work material, these cams are replaced byother cams. Also, the clamp member 12 is removed from the arm 24 bydisconnecting bolts 82 and is replaced by a different clamp memberhaving a shape corresponding with the desired stitching pattern. Tochange the movement relationship of the cams relative to the crank shaft81 of the sewing machine 18, the change gears 69 and 70 in the geartrain can be changed.

On the surface of the upper cam 36 are positioned a plurality ofactuator elements 86 which operate respective switches within a controlhousing 87 extending closely above the top of this cam. These actuators86 produce the desired sequence of operations for the particular patternbeing sewn, and when the upper cam 36 is changed to do a differentpattern, then the replacement cam has actuators on it also in the properlocation to produce the sequence for the new pattern. In this system asshown, when the stitching pattern is completed, then the clutch 63 isde-energized and the brake 64 is energized to stop the shaft 65. Themain drive motor 60 continues to rotate.

In FIGURE 3A is shown the operating circuit for the clutch 63 and brake64. The clutch 63 is engaged when its magnet wind-ing 90 is energized,and similarly the brake 64 engages when its magnet winding 91 isenergized. A direct current circuit 92, 93 provides their power.Normally open relay contacts 101 are mechanically ganged with normallyclosed relay. contacts 102, and these are in series with the respectivewindings 90 and 91 and are controlled by a sew-cycle relay solenoid(FIG. 3). A pair of capacitors 94 are connected across the windings 90and 91 so as to maximize their speed of response. Even though the clutch63 and brake 64 are fastacting, there is momentum in the sewing machinesystem such that a few stitches occur before the sewing machine 18 isstopped completely.

Assuming that the machine 18 is sewing and is approaching the end of thestitching path P, just before the end of the stitching pattern, toaccommodate the momentum as discussed, one of the cam actuators 86 opensa normally closed cam switch 94 (FIG. 3), which ininterrupts an electricenergizing path to the relay winding 100, thus releasing the clutch andenergizing the brake winding 91. This control circuit (FIG. 3) issuitably energized by a source of power, for example 24 volts ofalternating current connected to the lines and 111.

'As the sewing speed slows down below a predetermined level, thespeed-sensing switch 83 (FIGS. 1 and 3) becomes closed. Thispredetermined level is set in accordance with the maximum sewing speedat which the locking mechanism 77 can be put into condition forengagement without damage to the system 10. Closure of the switch 83energizes a winding 96 of a solenoid air valve (not shown) causing theair cylinder 97 (FIG. 2) which has a piston rod 98 connected to alocking element 99 to push this element 99 against the perimeter of arevolving locking member which is in the form of a disc in the lockingmechanism 77. This revolving member 115 is secured to the shaft 76 andhas a pair of diametrically opposed lock-engaging means 116 in the formof recesses in the perimeter of the revolving member 115. It is notedthat the pulley 78 has a diameter twice that of the pulley 80, and sothe sewing machine crank shaft 81 makes two revolutions for each one ofthe revolving disc 115. Thus, the needle 16 makes two strokes for eachrevolutionof the locking disc 115. The lock-engaging notches 116 arepositioned so that the needle 16 is locked up in the desired elevatedposition when the dog 99 engages into either of them.

The locking mechanism 77 includes a block 113 fixed to the machine frame114 and having a channel 117 in which the dog 99 can be slid andincludes a front plate 118 which covers the dog and disc 115. At theinstant when the dog '99 touches the perimeter of the disc 115, thisdisc is continuing to turn as the machine 18 is coming to a stop. Thusthe disc 115 turns sufficiently for the dog 99 to drop into one of therecesses 116, locking the needle up. The dog has a laterally projectingpin 119 projecting into a slot in one end of a bell crank lever 120which is pivoted at 121 and has a leg 122 for actuating a pair ofswitches 123 and 124. The switch 123 includes normally-closed contacts123a and normally-open contacts 123b, and similarly the switch 124includes normally-closed contacts 124a and normally-open contacts 124b.When the dog 99 moves into a notch 116, the leg 122 closes thenormally-open contacts 123b, which energizes a winding 125 of a solenoidair valve (not shown) causing lift means 126 (FIG. 1) to raise the arm24. This lift means includes an air cylinder 126, having a verticalpiston rod 127 with a horizontal bar 128 extending across the top. Aslippery plate 129 covers the top of this bar 128 providing easy slidingmeans for enabling the arm 24 to be moved rapidly while supported on thelift means. For example, this slide plate 129 is made ofpolytetrafluoroethylene.

Closure of the switch 123b also energizes a winding 130 of a solenoidair valve (not shown) causing the arrester foot 28 (FIG. 1) to belifted, for example, as shown in said copending application.

In the event that the locking disc 1 15 happens to be in such a positionthat it comes to rest before the dog 99 is engaged, that is, the lockingmechanism is in an intermediate condition not fully engaged, then thedisc 115 is automatically turned further by means producing a briefelectrical pulse so that the dog will fully engage, as will beexplained. When the dog rests against the perimeter of the disc 115, thenormally closed contacts 124a are opened, and the normally open contacts124b become closed. The means for producing a brief electric pulseincludes the switch 124b which discharges a relatively large pulse fromthe charged capacitor 133 through a time-pulse adjusting resistor 134and through the relay winding 100, controlling the brake and clutch.Thus, for a'brief instant the brake is released and the clutch isre-engaged, with the main drive motor 60 running continuously, so as toturn the sewing machine pulley 80 a sufficient distance that the dog 99does become engaged. The capacitor 133 is energized through a chargingcircuit including a peak-current limiting resistor 135 and a diode 136and through the contacts 124a which are closed only during the period oftime when the locking dog 99 is out. The resistor 134 is adjusted to avalue to provide a current pulse of the proper duration to provideonehalf revolution of the locking disc 115. This is suflicient rotarymotion to assure that the dog 99 engages, without producing an undueamount of mechanical shock or torque. Engagement of :the lock dog 99causes the switch 123b to become'closed so as to raise the clamp 12aandto raise thearrester foot 28, as discussed befOre.

Now that the clamp 12 is up, the present production cycle. is ended, andthe system 'is'awaiting a new signal before beginning the nextproduction cycle. When the lift means 126 raises the clamp, an arm 131projecting from the piston rod 127 closes a normally open switch 132(FIG. 1, and top of FIG. 3) in a start-cycle circuit.

It is noted that. there are switches 139, 142, and 149 '(FIG. 1) whichare actuated by a sector-shaped plate 140,. depending upon whether thelever 35 is in such a position that the roller 44 engages the cam 37 orthe lever 35 is moved away from the cam 37. When the lever 35 isfollowing the cam 37, the clamp 12 is in. the sewing station, and whenit is not, the clamp is out of the sewing station. The switch 139 isnormally closed, and it is held open by the sector shaped member 140only when the lever 35 is in position for the roller 44 to engage andfollow the cam 37, that is,'when the clamp is in the sewing station. Thesector shaped member 140 is rigidly attached to the lever 35 by a sleevewhich surrounds the pivot 47. The switch 149 includes two sets ofnormally open contacts 149a and 1491) (FIG. 3). These contacts 149a and14% are held closed when the clamp is in.

As mentioned closely above, the clamp is up and the start of the nextproduction cycle is being awaited. When it is desired to start the nextproduction cycle, an electrical signal is fed in through a lead 148,through the clamp-up sensing switch 132, and through a cam switch 159 toa solenoid 150 of a cycle start relay. This relay winding 150 controlsthree sets of contacts: normally open contacts 151 and 152, and normallyclosed contacts 153. The energization of the start relay 150 closes theself-holding contacts 151 to maintain relay 150 energized until the camswitch 159 is actuated into its open position. This cam switch 159becomes opened by movement of the cam 36 during the sewing operation, asexplained further below. The put-pose of this cam switch 159 is toprevent inadvertent recycling until the sewingoperation is completed.

The energization of the start relay 150 also opens the normally-closedcontacts 153. The purpose of these contacts 153 is to serve as aninterlock to insure that the dog 99 does not become re-engaged afteranew start signal has been given.

The closure of the contacts 151 serves to energize the winding 138 of aclamp-out solenoid valve, which controls the double-acting cylinders 49and 50. Thus, the

piston rod 53 is extended and the rod 51 is retracted to slide the armalong the elevated slide pad 129 until the clamp 12 is moved out of thestitching station, that is, so as to be directly positioned above thenext workpiece W-2. Because the clamp was raised before it was shiftedinto position over the next workpiece W2, the completed workpiece Wremains in the sewing: station.

When the clamp 12 is in its out position correctly located above the newworkpiece W-2, a normally open switch 142 is closed by the sector shapedmember 140. This energizes a winding 143 of a solenoid air valve (notshown) causing the lift means 126 to retract to lower the arm 24 so thatthe clamp 12 now firmly engages the new workpiece W-2. At the same time,a winding 144 of a solenoid valve which controls the thread cut offoperation is, energized so as to cut the top thread 27 and the bottomthread 28, forexample, as described in said copending application. 1

The completed workpiece W can now be taken away manually orautomatically. In this example, the clamp 12 includes laterallyextending fingers 160 having friction gripping tips 161, for example ofsponge rubber, which will engage down upon the completed workpiece Wwhen the clamp is lowered. These fingers 160 will serve to move thecompleted workpiece W from the stitching station over to a-dischargestation D while the next piece W-2 is being brought into the stitchingstation. When the clamp 12 is raised later on at the completion of theworkpiece W-2,.-thcn the workpiece W can be removed from the dischargestation D either manually or automatically.

Also, the winding 146 of a solenoid valve is energized by closure of thecontacts 142, causing the cylinder 97 (FIG; 2) to retract the lockingdog 99, thus opening the switch 12417 and allowing the switch 123a toclose and closing the switch 131 to recharge the capacitor 133.-

Asexplained above, the clamp-out contacts 142 are closed so that theclamp-down control winding 143 has been energized, and the clamp 12 hasnow been lowered down'upon the .next workpiece W-2. This closes theswitch 145, and so the winding 147 of a solenoid air valve is energizedso that the piston rod 51 becomes eX- tended and the rod 53 becomesretracted, which moves cam follower rollers 43 and 44 back intoengagement with the cams. Normally open switch contacts 149:: are nowclosed by the sector shaped member which partially closes a circuit tothe sew cycle relay 100. Also normally open switch contacts 14% areclosed when the clamp 12 is brought into the sewing station, whichenergizes a control winding 148 to lower the arrester foot 28 onto thenew workpiece W-2. Moreover, a control winding 154 is energized toretract the thread cutting mechanism.

The clamp 12 is now positioned in the same location as it was when thepreceding stitching pattern was completed. The stitching pattern whichis about to be made is made in the reverse direction from the precedingone. The reason for doing this reverse stitching is that it enables eachpattern to be begun at exactly the same point where the preceding onewas ended. This provides maximum production when stitching a patternhaving the ends of its path P separated, because it avoids the timewhich would otherwise be required to re-position the cams so as toprovide the same starting point each time, but this repositioning to thesame starting point can readily be accomplished if desired.

I In order to accomplish the reverse stitching of each successivepattern, the cams 36 and 37 are turned only onehalf of a revolutionduring each pattern, and they are shaped so that the second half of eachcam produces the desired reverse movement of the clamp 12.

There are interlock means 156 responsive to the following conditionswhich control a normally open safety interlock switch 158. Thisinterlock switch 158 is not closed until the following conditions arepresent:

(1) Clamp 12 is down.

(2) Dog 99'is retracted to unlock sewing machine 18. (3) Thread cut offmechanism is retracted.

(4) 'Arrester foot 28 is down in operating position.

The switch 149a serves as a further interlock means to assure that:

(5) Clamp 12 is in sewing position.

When these five conditions are met, then the switches 158 and 149a areclosed. The contacts 152 became closed upon energization of the startrelay 150, and so the sew cycle relay 100 becomes energized to releasethe brake and engage the clutch, thus initiating the high speed sewing.It is noted that the relay 100 also includes self-holding contacts 103which are normally open but which become closed by energization of thewinding 100. Thus, the next sewing operation now begins.

. As soon as the cam 36 moves, the actuator 86 moves so that the camswitch=159 is momentarily opened. Thus, the relay 150 is de-energized toopen the contacts 151 and 152 to prevent inadvertent re-cycling of thesystem unless the proper sequence has been completed.

It was explained that one of the actuators 86 is positioned to open thecam switch 94 just before the end of the sewing pattern. The particulardistance, i.e. lead time,

before the end of the sewing pattern depends upon the speed of thesewing machine 18 and its momentum and operating characteristics. -Intypical applications this lead time is in the range from two to sixstitches before the end of the stitching pattern.

It was explained that each successive workpiece can be sewn in theopposite direction; this is desirable where the stitching path commencesand ends at different points in the workpiece W, i.e. an open pattern.However, there are closed patterns, that is, the stitching path-Pterminates near where it commenced. In such a case each workpiece issewn in the same direction. If desired, the cams 36 and 37 can be shapedand the actuators 86 arranged such that open patterns are all sewn inthe same direction, as indicated further above. This system is extremelyflexible and can be set up so as to sew larger patterns or smallerpatterns, complex patterns or rela tively simple patterns in accordancewith this specification.

From the foregoing description, it will be understood that the automaticsewing machine system of the present invention is well adapted toprovide the many advantages and features set forth and that by means ofvarious changes, the system described can be adapted for a wide varietyof automatic production applications in accordance with the teachings ofthis specification, and that the scope of the present invention includessuch modifications and changes as claimed.

What is claimed is:

1. An automatic sewing machine system comprising a movable needle forstitching fabric workpieces, drive means connected to the needle formoving the needle to form stitches, brake means connected to said drivemeans for stopping the needle, a motor, clutch means connecting saidmotor to said drive means for providing power thereto, locking meansconnected to said drive means and engageable in a predetermined positionfor locking said drive means to secure the needle in an inactiveposition, speed sensing means responsive to the speed of said drivemeans for conditioning said locking means toward engagement after thespeed of said drive means has fallen below a predetermined safe level,and means responsive to said drive means in other than saidpredetermined position for momentarily releasing the brake means andre-engaging the clutch means for moving said drive means until saiddrive means reaches said predetermined position for engagement of saidlooking means.

2. An automatic sewing machine system as claimed in claim 1 and whereinsaid clutch means and brake means are electrically actuated and saidmeans for momentarily releasing the brake means and for re-engaging theclutch means includes means producing a brief electrical pulse.

3. An automatic sewing machine system as claimed in claim 2 and whereinrelay means are connected to said clutch means and to said brake means,and said pulse means includes a capacitor and a charging circuit forsaid capacitor, and a discharging circuit extending from said capacitorthrough said relay means momentarily releasing the brake means andre-engaging the clutch means upon discharge of said capacitor throughsaid relay means.

4. An automatic sewing machine system as claimed in claim 3 and whereinsaid discharging circuit includes a variable resistor adjusting theduration of said electrical pulse.

5. An automatic sewing machine system comprising a movable needle forstitching fabric workpieces, drive means connected to the needle formoving the needle to form stitches, brake means connected to said drivemeans for stopping the needle, a motor, clutch means connecting saidmotor to said 'drive means for providing power thereto, locking meansconnected to said drive means and engageable in a predetermined positionfor locking said drive means to secure the needle in an inactiveposition, said locking means including a revolvable member connected tosaid drive means and revolving when said drive means is moving, saidrevolvable member having lock-engaging means thereon, a locking elementhaving a retracted position, an intermediate position touching saidrevolvable member and a forward position engaged with said look-engagingmeans, speed sensing means responslve to the speed of said drive meansfor moving said locking element toward engagement after the speed ofsaid drive means has fallen below a predetermined safe level, and meansresponsive to said locking element in said intermediate position formomentarily releasing the brake means and re-engaging the clutch meansfor moving said drive means until said drive means reaches saidpredetermined position for engagement of said lockmg :means.

6. An automatic sewing machine system as claimed in claim 5 and whereinsaid lock-engaging means includes at least one recess in the perimeterof said revolvable memher and said locking element is a dog which ismovable toward engagement with said recess, said dog in its intermediateposition resting against the perimeter of said disc wlthout engagementin said recess, and said dog in its forward position engaging in saidrecess and positively locking said revolvable member against revolution.

7. An automatic sewing machine system as claimed in claim 1 andincluding a movable clamp member for holding the workpiece and operableto move the workpiece with respect to the movable needle for producing adesired pattern of stitches in the workpiece, cam means connected tosaid drive means and driven thereby for moving said clamp, said lockingmeans looking said cam means simultaneously with the locking of theneedle, and double-acting means connected to said clamp member andoperable while said locking means is engaged for moving said clampmember independently of said cam means.

8. An automatic sewing machine for stitching a pattern in a fabricworkpiece comprising a movable needle at a sewing station, drive meansconnected to the needle for moving the needle to form stitches, amovable clamp member for holding the workpiece and operable to move theworkpiece with respect to said sewing station for producing a desiredpattern, lever means connected to said clamp member, cam means connectedto said drive means and engaging said lever means for operating theclamp member to move the workpiece with respect to said sewing station,locking mechanism for locking said needle and for locking said cam meansin a predetermined position, double-acting means connected to said levermeans and having a first condition of operation causing said lever meansto follow the movement of said cam means during stitching and having asecond condition of operation for moving said lever means and clampmember independently of said cam means when said cam means and needleare locked for moving the clamp member in and out of the sewing stationfor transferring workpieces with respect to the sewing station.

9. An automatic sewing machine system as claimed in claim 8 and whereinsaid double-acting means in said first condition provide a spring-likeforce for holding said lever means in operative engagement with themoving cam means thereby to follow the movement of said cam means.

10. An automatic sewing machine system as claimed in claim 9 and whereinsaid double-acting means are long stroke double-acting air cylindersproviding a spring-like force for holding said lever means in operativeengagement with the cam means during movement of said cam means.

11. An automatic sewing machine system as claimed in claim 8 whereinsaid clamp member has laterally projecting elements thereon enablingsaid clamp member to engage more than one workpiece simultaneously.

12. An automatic sewing machine system as claimed in claim 8 andincluding an arm connecting said clamp 11 member-t0 said levermeans,.-lift means engageable beneath said arm for raising said arm tolift the clamp member, said lift means including a horizontal bar havinga low friction surface engaging thelower surface of said arm, and saidarm when elevated on said bar being readily slidable therealong formoving the elevated clamp member.

13. An automatic sewing machine system for stitching a predeterminedpattern of stitches in successive fabric workpieces-andwherein saidpattern of stitches commences and terminates at points which are spacedapart in the fabric workpiece comprising a movable needle at a,stitching station, drive means connected to the needle for moving theneedle to form stitches, a movable clamp member operableto move theworkpiece at the stitching station relative to the needle to producesaid pattern of stitches in the workpiece, cam means driven by saiddrive means for controlling the movement of said clamp member at thework station, lock mechanism for locking said cam means at thecompletion of one stitching pattern, control means for removing thecompleted workpiece from said stitching station, for introducing asecond workpiece into the stitching station in an initial position whichis the same as the final position of the completed workpiece, and forunlocking said cam means, and for starting the stitching of said secondworkpiece, and said cam means being arranged to stitch the pattern inthe second workpiece in the reverse direction from the precedingworkpiece.

14. An automatic sewing machine system as claimed in claim 13 andwherein said drive means is connected to both said needle and said cammeans, said locking mechanism simultaneously locking said cam means andsaid needle means, and double-acting means controlled by said controlmeans for moving said clamp member while said locking mechanism islocked for transferring successive workpieces with respect to thestitching station. 15. An automatic sewing machine system for stitchinga pattern in a fabric workpiece comprising a movable needle at a sewingstation, drive means connected to the needle for moving the needle toform stitches, a movable clamp member holding the workpiece and operableto move the workpiece with respect to said sewing station for producinga desired pattern of stitches, lever means connected to said clampmember, cam means connected to said driving means and engaging saidlever means for operating the clamp member, switch means connected tosaid driving means for controllingthe operation thereof, said switchmeans being positioned adjacent to said cam means, a plurality ofactuator elements mounted on said cam means in positions to engage saidswitch means for actuating said switch means to control the operation ofsaid drive means, lock means for simultaneously locking said needle andsaid cam means, said lock means being controlled by said switch means,and double-acting means holding said lever means in cam-followerrelationship with said cam means when said lock means is unlocked, andsaid double-acting means moving said lever means for moving said clampmember independently of said cam means during the engagement of saidlock means.

References Cited UNITED STATES PATENTS 1,603,644 10/1926 Sibbald et al112-102 2,612,127 9/1952 Hayes. 2,836,276 5/1958 Schwab et al. 2,920,2215/1960 Schwab. 2,921,547 1/1960 Artzt et a1. 2,939,414 6/1960 Slinn.13,001,489 9/1961 Bond et al. 3,008,437 11/1961 Herr. 3,084,640 4/1963Hayes ct :11. 3,170,423 2/ 1965 Henebry.

IORDAN FRANKLIN, Primary Examiner.

JAMES R. BOLER, Assistant Examiner.

1. AN AUTOMATIC SEWING MACHINE SYSTEM COMPRISING A MOVABLE NEEDLE FORSTITCHING FABRIC WORKPIECES, DRIVE MEANS CONNECTED TO THE NEEDLE FORMOVING THE NEEDLE TO FORM STITCHES, BRAKE MEANS CONNECTED TO SAID DRIVEMEANS FOR STOPPING THE NEEDLE, A MOTOR, CLUTCH MEANS CONNECTING SAIDMOTOR TO SAID DRIVE MEANS FOR PROVIDING POWER THERETO, LOCKING MEANSCONNECTED TO SAID DRIVE MEANS AND ENGAGEABLE IN A PREDETERMINED POSITIONFOR LOCKING SAID DRIVE MEANS TO SECURE THE NEEDLE IN AN INACTIVEPOSITION, SPEED SENSING MEANS RESPONSIVE TO THE SPEED OF SAID DRIVEMEANS FOR CONDITIONING SAID LOCKING MEANS TOWARD ENGAGEMENT AFTER THESPEED OF SAID DRIVE MEANS HAS FALLEN BELOW A PREDETERMINED SAFE LEVEL,AND MEANS RESPONSIVE TO SAID DRIVE MEANS IN OTHER THAN SAIDPREDETERMINED POSITION FOR MOMENTARILY RELEASING THE BRAKE MEANS ANDRE-ENGAGING THE CLUTCH MEANS FOR MOVING SAID DRIVE MEANS UNTIL SAIDDRIVE MEANS REACHES SAID PREDETERMINED POSITION FOR ENGAGEMENT OF SAIDLOCKING MEANS.